youll find soon enough that its not JUST talking to a corpse for jinwoo anymore as the shadow monarch he can tap into a souls sentience and change the course of its decision making, so the pep talk he gave igris was just igris making a choice, the chances are to test the monarchs strength but mostly resolve and willingness to lead, that is why the summoning of igris, if it were to come down to level and strength, should have ultimately failed